Desulphurizing hydrocarbon oils



Patented Dec. 12, 1933 DESULPHURIZING nYnRocAaBoN or s Robert F.Ruthruff, Hammond, Ind, assignor to Standard'Oil Company, Whiting, Ind.,a corporation of Indiana No Drawing. Application July 5, 1929 Serial No;376,290 1 9 Claims.

The present invention relates to improvements in desulphurizinghydrocarbon oils, and more particularly the lower boiling pointdistillates such as distillates in the gasoline and kerosene boilingpoint range. It has been found particularly suited for use in connectionwith cracked distillates from high sulphur oil, such as Lander andWinkler oils which distillates contain sulphur bodies of a highlyrefractory type and which are diflicult to remove.

In accordance with the present invention, the alkali metals such assodium and potassium are preferably employed to effect thedesulphurizing. The metal used may be employed in lumps (massive) inoperating in accordance with the present invention, and metals fusibleat the temperature of operation are then preferred.

In carrying out the invention, the active metal is employed in aproportion equal to or substantially exceeding the atomic equivalent ofthe amount of sulphur present. In general, the atomic proportion of themetal to the sulphur should exceed 1 to 1, and proportions in excess of3 to 1 are preferred. The distillate and the active metal are heatedtogether to a temperature of at least 400 F. and preferably notexceeding 650 F. In general a temperature of at least 500 F. ispreferred. The operation is conducted under pressure, generally inexcess of 150 lbs. per sq. in. and preferably from 200 'to 300 lbs. persq. in. Higher pressures are employed when lower boiling constituentsare present. Under these temperature and pressure conditions thedistillate is of course substantially in the liquid state and the alkalimetal is in the molten condition.

As an example of the operation, a gasoline derived by a vapor phasecracking operation from a high sulphur crude oil was treated with lumpsodium, the atomic ratio of sodium to sulphur being 4 to 1 at atemperature of 575 F. and a pressure of 290 lbs. per sq. in. for threehours with vigorous agitation, the percentage of sulphur being reducedfrom an initial value of 0.182 to 0.087. The same gasoline treated witha higher proportion of sodium, the atomic proportion of sodium tosulphur being 6.3 to l, at 575 F. under 300 lbs. per sq. in. pressure,the sulphur was reduced to 0.016%.

To further illustrate the invention, the 225 to 420 F. cut of anotherdistillate derived by an ordinary cracking process from asulphur-containing crude was treated in the presence of an inertsubstantially sulphur-free heavy oil having an initial boiling pointabove 600 F. with sodium in an atomic ratio to the sulphur of 4.65 to 1at a temperature of 560 F. and a pressure of 175 lbs., the sulphurcontent being reduced from 0.473% to about 0.1%. It is thus apparentthat the admixture of a heavy oil which, has an initial boiling pointsubstantially above the end point of the distillate oil and is thereforereadily separable from the low boiling distillate, improves theeffectiveness of the action of the active metal.

Other alkali metals, such as lithium, potassium and the like aresimilarly efiective.

When sodium or other active alkali metal is employed in lump form, itmay be screened or otherwise separated out of the treated oil and reusedfor the treatment of fresh sulphurcontaining distillate, suflicientadditional fresh metal being supplied to bring the atomic ratio of metalto sulphur to the desired figure. However, since more sodium isapparently used up in the reaction than that calculated from the amountof sulphur removed, an excess over such calculated amount should besupplied for replenishment or the amount of sodium present will beinsufficient to effect the desired desulphurization. Thus, in anoperation conducted with sodium in lump form in an atomic ratio relativeto the sulphur of 4 to 1 on a sulphurcontaining pressure distillate outhaving an approximate boiling range of from 225 to 420 F., at atemperature of 575 F. and a pressure of 235 lbs. per sq. in. for threehours, in the first use of the sodium, the sulphur was reduced from aninitial percentage of 0.764 to 0.067. On the second use, it was reducedfrom 0.764 to 0.092, and on third use from 0.764 to 0.186. Thus thesodium or other active metal may be reused as long as the amount presentis sufficient for effective reaction, additional metal being added asrequired to maintain effectiveness.

The operation may be conducted in an atmosphere of a gas inert to theoil and alkali metal under the conditions of the process, such ashydrogen or nitrogen. This serves to increase the effectiveness ofsulphur removal with a given ratio of metal to sulphur.

I claim:

1. In a process of desulphurizing a low boiling hydrocarbon distillatelying substantially within the gasoline-kerosene boiling point range thestep which consists in coagitating said distillate, in substantiallyliquid state, and an alkali metal in molten form at a temperaturesubstantially within the range of 450 F. to 650 F. under a pressure ofat least about 150 pounds per square inch.

2. The process as in claim 1 in which the alkali metal is metallicsodium.

3. The process as in claim 1 wherein the distillate prior to treatmentwith the alkali metal, is admixed with a low sulphur oil, the initialboiling point of which is substantially above the end point of saiddistillate.

4. The process as in claim 1 wherein the distillate and alkali metal arecoagitated in an atmosphere of a gas inert to the oil and alkali metalunder the conditions of the process.

5. The process as in claim 1 wherein the excess alkali metal isseparated from the treated distillate, and coagitated with a freshportion of untreated distillate and a fresh portion of alkali metalunder said conditions of temperaa ture and pressure. p

6. The process as in claim 1 in which at 7 .inch.

8. The process as in claim '7 in which the alkali metal is metallicsodium.

9. The process as in claim 7 in which at least three atoms of alkalimetal are used for every atom of sulphur in the distillate to bedesulphurized.

ROBERT F. RUTHRUFF.

